U.S. Pat. No. 4,739,533 entitled "Machine for Scraping off the Plastic Coating of a Used Wire" of the same applicant of this application disclosed an apparatus comprising a low speed feeding roller provided with teeth thereon, and a high speed scraping roller mounted with steel brush wheels so that the pre-cut used wires are fed into the apparatus and the plastic coating is scraped off by the steel brush wheels to obtain substantially exposed copper wire.
However, the apparatus only provides the way for scraping plastic coatings from the insulated wires, from which the plastic coatings should be further separated from the stripped copper wires.
Accordingly, a set of systematic equipments for classifying and separating the copper, the ferrous material, and the different plastic materials is still expected and is then invented by the same applicant.